Electrical indicator.



PATENTED SEPT. 19, 1905.

.H. LEMP. ELEGTRIGALINDIGATOR. APPLICATION FILED MAYS 1903 2 SHEETS-SHEET 1.

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ITO-800,117. I PATENTED SEPT. 19, 1905.

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ELECTRICAL INDICATOR. APPLICATION FILED MAY 5, 1903.

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Hermann Lemp By W 14.15 7 J o ttiy.

UNITED STATES PATENT OFFICE.

HERMANN LEMP, OF'LYNN, MASSACHUSETTS, ASSIGNOR TO ELIHU THOMSON, OF SWAMPSOOTT, MASSACHUSETTS.

' ELECTRICAL INDICATOR- To aZZ whom it may concern:

Be it known that I, HERMANN LEMP, a citizen of the United States, residing at Lynn, in the county of Essex, State of Massachusetts, have invented certain new and useful Improvements in Electrical Indicators, of which the following is a specification.

The present invention relates to temperature-indicators, and has for its object to provide an indicator for steam-generating systems,'and more especially those including a generator of the so-called flasher type, whereby the Operator can determine the temperature of the generator or ofthe steam delivered thereby between certain predetermined limits for the purpose of guiding him in the manipulation of the devices feeding water to the generator and fuel to the burner.

For a consideration of what I believe to be novel and my invention attention is called to the description and claims appended thereto.

In the accompanying drawings, Figure 1 illustrates my invention as applied to an automobile, parts of the latter being broken away; and Fig. 2 is a diagram of the temperatureindicator.

Referring to the drawings, in which similar numerals of reference indicate correspondingparts, 1 represents a boiler of suitable character In the present instance it is of the flasher type, 2 being an engine, and 3 asteamsupply connection therefor. The steam-supply pipe contains a tubular casing 4, through the length of which the steam passes from the boiler to the engine, and arranged in the easing is a thermostat 5, composed of twometals having different coefficients of expansion. A tube of copper 6 and a core of steel 7 will be found to work satisfactorily. The tube and core are rigidly secured together at their inner ends, as by a pin, whereas the outer ends are free to move independently. The outer end of the tube is rigidly secured to a stationary plate 8, by means of which the casing 4 is fastened to the body of the vehicle, as shown in Fig. 1. The plate 8 supports a pivoted contact-lever 9, which is maintained in constant relation to the projecting end of the steel core 7 by means of a helical extensionspring 10, alsosupported by the plate 8, the,

. the action of the thermostat. At the free end Specification of Letters Patent.

Application filed May 5 1903. Serial No. 155,726.

Patented Sept. 19, 1905.

y of the spring-actuated contact-lever 9 and ar-.

ranged on opposite sides thereof are contactpoints or set-screws'll and 12, that are adjustable relatively to each other in supporting-lugs on the plate 8, so as to regulate the length of throw of the lever between the contact-points, thereby rendering the action of the thermostatic rod moreor less sensitive.

The contacts 11 and 12 are connected, re-

spectively,.by conductors with spring-con taots 13 and l t of a manually-actuated switch 15, the latter being provided with contactblades-16 and 17 for the contacts 13 and lt, respectively, forming a double-throw switch device. The switch 15 is connected in circuit with a suitable source of current, such as a dry battery 18, and with a suitable indicating means, such as a buzzer 19. One side of the battery 18 or other source of current-supply which is fixed adjacent the controlling-stand or on the heel-board of the body of the vehi cle, as shown in Fig. 1. The manually-com trolled switch 15 is also arranged on the heelboard to be conveniently within reach of the operator.

In practice I have found the temperature of the steam best suited to meet average conditionsof work to be about 650 Fahrenheit. The limits within which the temperature of the steam may vary and still produce efiicient results I have found to be about50 Fahren: heit above and the same amount below the normal temperature650 Fahrenheit. I do not wish to be-understood, however, as being limited to these or any other specific temper atures, since for.different conditions other The thermostat spring, makes contact with the contact-point r 11. At alow temperature of the steam the tube contracts faster than thecore, thereby causing the lever 9 to move into engagement with the contact-point 12 against the influence of its spring by means of the core impinging upon said lever. Thus by the action of the thermostat the contact-lever 9 is adapted to be placed in operative relation to the buzzer,

19 at extremes of temperature variation of the steam and cooperating with and depending upon the manually-controlled switch 15 for closing the circuit.

A suitable burner 21 is placed below the boiler-tubes and is supplied from a tank 22, that is under suflici'ent pressure to force the fuel into the burner. Any equivalent means can be substituted for the tank under pressure for forcing fuel into the burner. Between the tank and the burner is located a valve 23, by means of which the amount of fuel delivered to the burner can be varied to suit the conditions of the steam as indicated by the thermostat. No means are shown for forcing water or other fluid to be vaporized into the generator; but it is to be understood that a pump and suitable regulating devices are to be employed.

Should it be desired to operate the boiler within a more limited range of temperature variation, the circuit-closing lever 9 must be rendered more sensitive to slight changes of the thermostat. In order to accomplish this, the contact-points 11 and 12 are adjusted inwardly toward each other, thereby diminishing the length of throw of the lever necessary to make contact.

The manually-controlled switch 15 may with advantage have an initial or neutral position wherein it is out of contact with either of the spring-contacts 13 or 14 and is adapted to be manipulated by the operator when it is desired to ascertain the thermal condition of the steam. According to the direction of throw of the switch the temperature of the steam is determined. If thrown to the left or in the direction to close contact 13 and the buzzer operates, the temperature of the steam is too high. If moved in the opposite direction and the buzzer operates, the temperature of the steam is too low, whereas if the buzzer is silent in each of these cases a normal condition is indicated, the position of the contact-lever in the latter instance being intermediate and out of contact with contacts 11 and 12. After ascertaining the condition of the steam at which the boiler is operating the necessary correction, if any, of the supply of fuel or water, or both, is made to obtain normal temperature, whereupon the switch 15 may be moved to its opposite contact, so that the circuit will be completed when the opposite condition of the boiler is reached, due to the action of the thermostat, and the buzzer is thereby sounded to guide the operator in regulating the feed-supply to obtain the opposite effect, and so on repeatedly during the operation of the system.

The operation of the devices is positive and reliable, thereby al'l'ording an ellicient and dcsirable indicating means by which the temperature of the steam within predetermined limits can be readily (lOCOl'll'llllOLl at all times for facilitating the regulating of the fuel or water supply to suit various working conditions of the system.

From the foregoing it will be seen that in order to get an indication two separate actions take place: first, the automatic movement of the lever by the thermostat into engagement with one or the other of the adjacent contacts, and, second, the manual movement of the switch arm or lever into engagement with one or the other of its adjacent contacts. As before pointed out, the movement of the switch-arm can take place before or after that of the thermostatically-actuated lever, or the movements may be practically sinmltaneous. here the device is intended to respond to the temperature of the generator rather than of the steam, it should be applied to the generator direct rather than to a pipe leading therefrom.

In accordance with the provisions of the patent statutes 1 have described the principle of operation of the invention, together with the apparatus which I now consider to represent the best embodiment thereof; but 1 desire to have it understood that the :wparatus shown is only illustrative and that the invention can be carried out by other means.

hat I claim as new, and desire to secure by Letters Patent of the United States.

1. In a steam-generating system, for selfpropelled vehicles, the combination of a boiler, an engine receiving steam therefrom, and an electric indicating device which is sensitve to temperature variations of the steam delivered from the boiler, said device including a switch controlled from the vehicle-seat which in one position indicates high ten'i 'ierature of the steam and in the other position indicates low temperature.

2. In a steam-generating system for selfpropelled vehicles, the combination of a steamgenerator, an engine receiving steam therefrom, and an electric indicating apparatus sensitive to temperature variations of the steam delivered from the boiler, said apparatus including a manually-actuatcd switch and a signal device both located adjacent the vehicle-seat.

3. In a steam-generating system for selfpropelled vehicles, the combination of a steamgenerator, an engine receiving steam therefrom, a thermostat sensitive to the temperature of the steam supplied to the engine, an electric circuit, a signal device therein, a switch controlled by the thermostat, and a manually-actuated switch operative from the vehicle-seat, which cooperates with said thermostatically-actuated switch for ascertaining the temperature of the steam.

actuated switch for ascertaining the temperature of the steam. IO

4. In a self-propelled vehicle, the combination of a generator of the flasher type, an

stat located in said connection, an electric circuit, a signal device therein, a switch controlled by the thermostat, and a manually-actuated switch operative from the vehicle-seat, which cooperates with said thermostaticallyhand this 2d day of May, 1903.

, HERMANN LEMP. Witnesses:

DUGALD McK. MeKlLnor, JOHN A. MOMANUS.

engine, a connection between them, a thermo- 1 In witness whereof I have hereunto set my 

